Method of extracting and recovering molybdenum from its ores and concentrates.



H. A. DOE-RNER.

METHOD 0F ExTRAcTlNG AND RECDVERING MDLYBDENUM FROM ITS DRES ANDCDNCENTRATES.

APPLICATION FILED JAN. i8, 19H.

. l norman, or DENVER, comme.

Maraton or. nx'rnectrme AND nncovnnme MOLYBDENUM rnoiu Irs onus lArmconcrmnarns.

exact description of the invention, such asv will enable others skilledVin the art to which it appertains to make and use the same.

rIhe present invention relates to a method' for the extraction andrecovery of molybdenum from its ores and concentrates; andmoreparticularly to the recoveryo molybdenumoxid of commercial purityfrom .ores or concentrates; and especially from those ores andconcentrates which contain copper or other deleterious elements whichare not .separated by the usual methods of treatment'.

I have found that when molybdenum ores or concentrates or otherappropriate molyb- 'denum-containin materials are heated with vasuitable chlori to a sucient temperature to fuse the same and underproper conditions the molybdenum will distil ed in the form of volatilechlorids or oxychlorid's; and thatrom the distilled product molybdenumoxid can be readily .obtained by the action of water 4or steam,hydrochloric acid being atv the same time set free.

4In the practice of the invention, -the molybdenum-containin material,such as the molybdenumxsul ore, molybdenite, mixed with a suitablechlorid such as ordinary salt (sodium chlorid.),-is heated vto asuicient .temperature to form a fused bath and under appropriateconditions for com-v the chlorin bining the molybdenum with o' the ofthe ychlorid 'and for' distilling lresulting chlorids or oxychloridsthus formed. 'The action is promoted' by carryp ing out the operation inan oxidizing at-4 mosphere.

In the preferred practice of the invention, I use .a fusible chlorid,such as sodium `chlorid, and electrolyze a fused bath ,conA- taining thechlorid and the molybdenum Specification of Letters Patent.

Patented Apr. 8, I9I9.

v Application led January 18, 1917. Serial No. 148,081.

ore; and I will describe my invention more particularly in connectionwith such preferred embodiment.y

. In the accompanying drawings I have illustrated a suitable type ofapparatus/for e'ecting the extraction and recovery of the molybdenuml bythe use of a fused bath contalning the molybdenum ore and a chloridsuchas sodium chlorid.

cast iron or steel box 1 divided into three compartments. lThe hearth12, vWhere vthe,- fused salt is decomposed by the electric current, hasitsoorcovered with' a layer of a Huid metal such as molten lead which isadapted to combine with an alkali metal such as sodium to form anamalgam. The molten lead Hows continuously to the lWell 3 from whichv itis ejected by means of steam introduced through the pipe 9through theipe 10 and into the chamber 11, from where 1t Hows 'back through thechannel 12 to the hearth 2. v

v 'Ihe hearth is linedv with magnesite bricks i and is held 'in thefire-clay setting 5. @ver the hearth are thecarbon or graphite anodes asuspended by the terminal rods 7, which pass through the lire-clay cover6. 'Ihe molten lead forms the cathode and is connected with the terminal8.l

The gaseous products are drawn 0E from the-furnace through the flue 13to suitablecondensing chambers (not shown). The furnace is provided withcovers 14 to close the openings through which the material is introducedinto the furnace; and with a taphole 1 5 to enable the moltencontents ofthe furnace to be drawn-od as desired,

In the preferred-practice of the invention, a `mixture of salt-andmolybdenum ore is ted to the furnace .and a directcurrent of suitablevoltage and amperage is passed decomposed therein into molybdenumVoxidand hydrochloric acid by the action of steam -or Water. Thisdecomposition of the molybdenum chlorids and the formation of the oxidsand hydrochloric acid may with advantage 'be' carried on in thecondensing chamber itself. The hydrochloric acid canbe separated byevaporation or distillation and recovered, leaving behind the molybdenumoxid.

inasmuch as molybdenum also forms a number of oxids, as Well as a numberof chlorids, the final product Will vary according to the variations inthe chlorid distillate.

With o res containing sulids, such as molybdenite, air may be admittedto oxidize the sulfur and thereby assist the action of the chlorin withresulting economy in the use of the chlorid. Thus, Where, undernonoxidizing conditions the sulfur ,l of the molybdenum suld may combinewith the chlorin to form sulfur chlorid, under oXidizing conditions itmay be oxidized to sulfur dioxid so that less chlorin is required forthe reaction. The oxidization of the molybdenum sulid, and the action ofthe sulfur dioxid in setting free chlorin, which may supplement orreplace the electrolytically formed chlorin, Vmay be illustrated by thefollowing equations: v

The chlorin is moreover set free Within the reacting mass Where itcancombine with the molybdenuml to form volatile compounds. Molybdenum canthus be removed which, if no such chlorin were set free, would tend toremain in the slag in soluble form.

The setting free of the chlorin at the anode is accompanied byliberation of sodium at the cathode, and this sodium amalgamates withthe molten lead to form an amalgam which flows to the Well 3 from whichit is ejected by the jet 'of steam into the chamber l1, being decomposedby the steam into molten lead and into sodium hydroxid,V

which, at the high temperaturesused, is obtained in a fused andanhydrous state. The

Lacasse decomposition vof the steam by the metallic sodium to form thesodium hydroxid is accompanied by the formation of' hydrogen which maybe drawn off and allowed to es. cape or utilized in an auxiliary heateror for other purposes.

The fused caustic soda accumulates in the chamber 11 above themoltenlead and overflows the lip 17 into a suitable receiver (not shown). Theimpoverished amalgam con- 'sisting mainly of molten lead which has beenfurther heated by the reaction of the steam and sodium, flows ,back tothe hearth 2 through the channel 12. The molten lead cathode is thuscirculated from the hearth to the Well 3.and `back to the health,combining with the sodum set free from thebath and giving up the sodiumlon treatment with the steam.

The heating of the fused bath'canbe effected by the resistance of thecurrent passed through it, and the bath can thus be kept at the propertemperature by proper regulation of the current; but the heating actionof the current may' be supplemented by an auxiliary heater, andparticularly by the use of such an auxiliary heater to preheat the saltand ore mixture which is fed to the furnace.

Fusion of the salt and ore takes place at a temperature slightly above800 C., and I have found a temperature of about 000.o C. a satisfactoryoperating temperature for the molten bath.

While l have described ajtype of furnace particularly adapted to the'practice of the invention. l do not desire to limit myself to the use ofany particular type of furnace oreven to the electrolytic decompositionof the chlorid in a fused bath; although such an clectrolytic procedure,using a molten or liquid metal cathode, l consider to be a particularlyvaluable embodiment of my invention and one having many advantages.

When the invention ispractised Without -the electrolysis of a fusedbath, a mixture of molybdenite andl salt, for example, can be heated tothe proper temperature in any suitable manner and subjected to anoxidizing atmosphere so that the chlorids 'or oXy# chlorids ofmolybdenum will distil 0H in a manner similar to that which T havealready described. Thus, for example, Where the mosphere by injectingair into the fused bath, the sulfur dioxid formed by the oxidizingatmosphere and the sulfur of the suld (molybdenite) reacts with moreoxygen and with the salt to form chlorin, which combines with themolybdenum to lform volatile compounds that distil off in 'a mannersimilar to that already described. Tn this 'case the reaction of thesulfur, oxygen (from the oxidizing atmosphere) and salt, furnishes ico`mixture of molybdenite and salt is heated to fusion, and'subjected tothe oxidizing ator sets -free chlorin which reacts in 'much the samemanner as the chlorin set free by electrolysis.

When the electric current islused, its action, aside from its otheradvantages and functions, assists the distillation and is a convenientmetliodof maintaining the desired ,temperatllre` It. has thev furtherimportant function, when used with a fused bath, of decomposing thechlorid and supplying active chlorin to the molybdenum of the'ore, aswell as of furnishing metallic sodium and caustic soda.

' l While I have described my invention more particularly with the useof sodium chlorid, it will be understood that other suitable chlorids,fusible. or. unusible, are adapted for use in the process.

I claim:

1. The method of recoverin molybdenum from its ores, concentrates another molybdenum-containing materials, which comprises heating thematerial to a sufficient temperature to form a fused bath and subjectingthe fusedl bath to the action of'free chlorin under proper conditions tocombine with and .to volatilize the molybdenum as chlorid or oxychlorid;substantially as de-l scribed.

2. The method of recovering molybdenum from its sulfid ores,concentrates and other molybdenum sulid containing materials, whichcomprises heating such materials in the presence of a chlorid to asufficient tem- A MS the presence of a source of chlorin to a sufficienttemperature to fuse the same, and to set free chlorin and under properconditions to volatilize the molybdenum in the form of chlorids oroxychlorids and recovering molybdenum oxid therefrom by the action ofsteam or Water; substantially as described.

d. The method of recovering molybdenum from its sullid ores,concentrates and other molybdenum sulfid containing materials,

which comprises heating the material with a chlorid to a suflicienttemperature to fuse the same and under proper oxidizing oonditions toset free chlorin and to volatilize the molybdenum as chloridl oroXychlorid and recovering molybdenumoxid therefrom by the action ofsteam or Water; substantially as described.

5. 'lfhe method of recoverin molybdenum from its ores, concentrates another molybv denum-containing materials, which comprises heating thematerial with a chlorid by means of an electric current to a suflicienttemperature to form a fused bath, and under proper conditions to setfree chlorin from said chlorid Within said bath to combine -with and tovolatilize the molybdenum as chlorid or oxychlorid; substantially asdescribed.

.6'. The method of recovering molybdenum from its ores, concentrates andother molybdenn-in containing materials, which comprises electrolyzingthe fused bath containing such material and a chlorid to volatili'ze themolybdenum as chlorid or oxychlorid; substantially as described.

7. rlhe method of recovering molybdenum from. its ores, concentrates andother molybdenum-containing materials which comprises electrolyzing afused bath containing such material and a chlorid to volatilize themolybdenum as chlorid or oxychlorid and recovering molybdenum oxid fromthe volatilized product b y the action .of steam or Water; substantiallyas described.

8. The method of, recovering molybdenum from its ores, concentrates andother molybdvenum-v containing materials, which comprises electrolyzinga fused alkali chlorid bath containing such material, using a fluidmetal cathode adapted to form an amalgam with the alkali metal, andthereby combining the molybdenum with chlorin and volatilizing themolybdenum chlorid or oxyc-hlorid thus formed, and at the same timeforming an amalgam with the cathode, decomposing the amalgam to formcaustic alkali, and returning the impoverished cathode metal for theformation of further amounts of a'malgam;,substantially as described.

9. 'The method of recovering molybdenum from its ores, concentrates andother molybdenumcontaining materials, Which com prises electrolyzing afused alkali chlorid bath containing-'such material and therebyvolatilizing the molybdenum as'chlorid or oxychlorid, combining thealkali metal set free with a fluid metal cathode in the form of anamalgam, and recovering molybdenum oXid from the volatilized chlorids bythe action of steam or Water; substantially as described. I

i0. The method of recovering molybdenum from its ores, concentrates andother molybdenum-containing materials, which comybirises electrolyzing afused sodium chlorid ath .containing such material, under oxidizingconditions, and thereby decomposing the sodium chlorid and combining thechlorin with the molybdenum in the form of volatile chlorids, separatingsuch volatilized chlorids and recovering molybdenum oxid therefrom bythe action of steam or Water,

combining the sodium set free With a molten lead cathode'in the form ofan amalgam, de-

composin the amalgam with steam to form caustic al ali and to recoverthe molten lead in an impoverished condition, and returning theimpoverished metal for combination with 5 further amounts of metallicsodium; substantially as described.

11. The method of recovering molybdenum from its ores, concentrates andother molybdenum containing materials, Which commeuue y bine witha'ndxto volatilize the molybdenum.

as chlorid or oxychlorid; substantially as described. Y .15

In testimony whereof I affix my signature.

HENRY ALFREDDOERNER. i

